1. Field of the Invention
The present invention relates to an anhydrous preparation for skin care applications, a method of applying an anhydrous skin care composition and a method of treating dry skin by applying an anhydrous skin care composition. It relates in particular to an anhydrous solid skin care composition.
2. Discussion of the Background
The skin care category consists of a broad array of products that treat dry skin. These products provide a wide range of perceived efficacies to the consumer, from xe2x80x9clightxe2x80x9d daily care products to therapeutic ointments and creams. The consumer selects a product from these categories, based on a self diagnosis of the severity of their dry skin symptoms. Generally, lotions are chosen to provide relief for symptoms at the lower end of the dryness scale, whereas creams and ointments are selected to treat symptoms of greater severity.
Dry skin problems of the greatest severity tend to be localized to small areas, such as hands, heels, elbows, etc. These parts of the body are consistently exposed to a harsh environment, for example, the hands are frequently washed with soap solutions and the elbows are repeatedly subjected to chafing and friction. Consequently, there is a propensity among consumers to use creams and ointments to treat these areas. There is one common complaint from consumers of these products, which is their perceived inherent greasiness. Creams and ointments are also messy to use, since to apply them, the consumer must either dip their hands in a jar or squeeze some product out on their fingers, and then rub the product on themselves. Due to these unappealing attributes, many consumers either use these products infrequently or completely avoid using them.
The primary goals of this invention are
1. to provide efficacious dry skin treatment,
2. that is not greasy,
3. in a convenient, easy to use form.
Matravers U.S. Pat. No. 4,996,239 reports a water resistant cream containing a synthetic wax of high molecular weight admixed with one or more hydrophobic silicones.
Edmundson et al. U.S. Pat. No. 4,873,078 reports a high-gloss, high-shine lipstick composition comprising isohexadecane in admixture with a lipstick formulation containing a heterogeneous mixture of at least two distinctly different colored dyes.
Deckner et al. U.S. Pat. No. 4,919,934 reports a wax based cosmetic stick comprising 10-50 wt. % of a wax and 5-90 wt. % of a poly xcex1-olefin.
Baker et al. U.S. Pat. No. 5,093,111 reports a lipstick composition comprising waxes, oils, colorants, cetearyl isononanoate, sesquistearate and isopropyl hydroxystearate.
Castro et al. U.S. Pat. No. 5,176,902 reports a colored cosmetic stick comprising 1-99% natural wax, 0.001-about 20% of a colorant which is an aluminum salt and 0.001-about 20% of a C12-60 fatty acid ester, in the absence of any C12-60 fatty acid.
Krzysik U.S. Pat. No. 5,288,482 reports a lipcare cosmetic composition comprising an emollient, a suspending agent, a coloring agent, and an organosilicon compound.
Dunphy et al. U.S. Pat. No. 5,310,547 reports a colored cosmetic stick comprising 0.5 to about 25% water, 1 to about 99% of a solidifying agent and 0.001 to about 20% of a colorant which is an aluminum salt.
Castrogiovanni et al. U.S. Pat. No. 5,505,937 reports a cosmetic composition comprising 1-70% of a volatile solvent, 0.1-15% of a silicone resin, 10-45% of wax, 5-50% of powder and 1-30% of oil.
Roberts U.S. Pat. No. 5,447,715 reports a non-aqueous suncare composition comprising a volatile silicone oil and a conventional non-aqueous waterproof sunscreen formulation.
Deckner et al. U.S. Pat. No. 5,593,662 reports a moisturizing lipstick composition comprising a lipophilic material, a moisturizer, a colorant and a coupling agent.
Berg et al. U.S. Pat. No. 4,814,165 reports a solid hydrated stick product comprising 15-40% of a volatile cyclic silicone, 2-15% of oils, 2-20% of waxes, 2-7% of polyethylene glycol sorbitan beeswax, 10-40% of water and 0.1-40% of a cosmetically acceptable functional ingredient.
Mercado et al U.S. Pat. No. 4,996,044 reports a creamy soft lipstick formulation which is anhydrous comprising an anhydrous base intermediate, a color intermediate, an organic high staining dye, a dispersing oil of organic pigments, an acrylate copolymer intermediate, acrylate copolymer, and fragrance.
In spite of the variety of skin care compositions available commercially, there remains room for improvement, providing the desired attributes of 1) effective treatment of dry skin; 2) no greasy feel; and 3) a convenient and easy to use form.
The present invention is directed to an anhydrous skin care composition comprising:
i) 5-50% of a wax;
ii) 10-80% of a hydrophobic liquid ingredient;
iii) 1-20% of a spreading agent; and
iv) optionally, 0-50% of a hydrophilic moisturizing ingredient.
The present invention addresses the complaints arising from cream and ointment users: this product takes the form of a solid stick, provides efficacy equal to a cream or ointment application, which is convenient, and has appealing aesthetics. With this product, treatment can be applied directly to the localized area of damaged, severely dry skin, without using one""s fingers. This product is anhydrous, and forms an occlusive barrier over the area of compromised skin. When this occlusive barrier is in place, the skin underneath it is shielded from further insult due to environmental factors, etc., and is given the opportunity to regenerate itself. The product is formulated to be non-greasy to the touch and quick absorbing, so that the perception of greasiness, stickiness and tackiness is eliminated.
The product is a combination of liquid and solid substances, which when melted together form a solid matrix, in which active ingredients are trapped. Hydrocarbon materials which are solid at room temperature and capable of forming crystalline matrices are preferably used to provide structure and rigidity to the stick. Hydrocarbon and silicone based liquid materials combine with the solids to reinforce the structure of the stick. Hydrophobic actives may be added to the stick by dissolving them into the stick base. Hydrophilic actives are stabilized in the stick by its physical structure.